Notes; Example -- Calculating The Volume Levels For Dial Tone - Cisco ATA186-I1 Installation And Configuration Manual

Appendix F Call Progress Tone Parameters and Defaults

Notes

Example -- Calculating The Volume Levels For Dial Tone

OL-1267-01
off-time controls the length of time between audible tones in milliseconds
•
(ms) expressed as an integer from 1 to 0x7FFFFFFF.
total time controls the length of time the tone is audible in multiples of 10
•
milliseconds (ms) expressed as an integer from 1 to 0x7FFFFFFF. A value of
0 causes the tone to remain audible indefinitely.
Frequency ranges from 0 to 4000 (Hz)
Transformed Frequency = 32767 · cos (2pi·Frequency/8000)
Transformed Amplitude = A · 32768 · sin (2pi·Frequency/8000)
The scaling factor A selects the volume level of the tone. To customize the
playback tone parameters, select a value for A based on the desired volume and
the number of frequency components in the relevant tone.
Table F-1 shows several values of A and the approximate volume level for each
value of A for tones that consist of one and two components.
A U.S. dial tone consists of two frequency components, 350 Hz, shown in this
example as level0, and 440 Hz, shown as level1.
To set the dial tone to a volume of -10dBm for a two-component tone at -10dBm,
use a multiplier of 0.35.
The formula for level0 uses this value of A in the Transformed Amplitude formula
as follows:
0.35 · 32768 · sin (2pi · 350 / 8000) = 3194
The formula for level1 is:
0.35 · 32768 · sin (2pi · 440 / 8000) = 4047
The approximate values to enter for level0 and level1 are 3194 and 4047,
respectively.
Cisco ATA 186 Installation and Configuration Guide
Playback Tone
F-3